Arc barrier for dynamo-electric machines



Dec. 1924- 1,519,270

E. B. SHAND ARC BARRIER FOR DYNAMO ELECTRIC MACHINES Filed Feb. 20, 1922 M NESSES: 10 6 7 INVENTOR 01m [770/19, Shand Patented Dec. 16, 1924;

UNITED STATES PATENT OFFICE.

ERROL B. SHAND, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ARC BARRIER, FOR DYNAMO-ELECTRIC MACHINES.

Application filed February 20, 1922.

T all whom it may concern Be it known that I, Ennon B. SIIAND, a subject of the King of Great Britain, and a resident of Pittsburgh, in the county of Al legheny and State of Pennsylvania, have invented a new and useful Improvement in Arc Barriers for Dynamo-Electric Machines, of which the following is a specification.

My invention relates to dynan'io-electric machines, and it has particular relation to are barriers adapted to be disposed intermediate adjacent sets of brushes to prevent arcs therebetween.

The object of my invention is to provide barriers which will suppress any are which tends to establish itself between adjacent brushes.

In the operation of direct-current machines, particularly rotary converters, there is a tendency for an are occurring under a commutator brush to extend along the commutator cylinder until it reaches from the brush or set of brushes under which it originated to the next adjacent set of brushes. Heretofore, a type of barrier has been employed in which a pointed inclined member was disposed adjacent to the moving commutator cylinder to scoop the are therefrom.

In order to prevent establishment of arcs of the character described, I provide arc barriers of insulating material disposed one on each side of each set of brushholders in such manner that the ends of the barriers adjacent to the commutator cylinder will be in proximity to the brushes, while the opposite or outer ends of the barrier are disposed relatively far apart in order to permit convenient adjustment of the brushes.

My barriers are constructed in such manner as to choke the arcs rather than to scoop them from the commutator cylinder. Also, my barriers are so arranged as to have no delicate pointed edge to become injured.

For a more thorough understanding of my invention, reference should be had to the accompanying drawings.

Figure 1 is an end elevational view of a single brush-holder provided with barriers constructed and arranged in acorn-dance with my invention.

Fig. 2 is a side elevational view of a poi" tion of a dynamo-electric machine provided with a plurality of sets of brush holders and Serial No. 537,813.

barriers constructed in accordance with my invention.

In Fig. l, I show a brushholder 3 provided with a brush box t and a brush 5. The brush 5 is adapted to co-operate with the segments of a commutator cylinder 6, of the rotor of a dynamo-electric machine. The brushholder 3 is supported by means of a member 7 which, in turn, is mounted on the frame 8 of the dynamo-electric machine.

The brushholders 3 are arranged in groups in side-by-side relation, as best shown in F 2. Each set of brushholder-s is provided with two are barriers 9 and 10. The barrier 9 is disposed on that side of the brushes from which the commutator segments approach. Its lower end is disposed in proximity to the commutator cylinder 6. It is supported from the member 7 by means of bolts 11.. Its main body portion is inclined at an angle to a radius drawn from the axis of the machine through the brushholder.

The are barrier 10 is disposed on that side of the brush set toward which the commutator segments move after passing the brush 5. The main body portion of the barrier 10 may be inclined with respect to a radius passing through the brushholder 3 and inclined oppositely from the barrier 9. The barrier 10 is provided with a relatively short end portion 12 disposed at an angle to the relatively long main body portion 10 and radially with respect to the commutator cylinder (3. The end portion 12 is disposed in close proximity to the commutator cylinder, so as to smother any are that tends to establish itself thereunder. The barrier 10 is mounted upon the brushbox t by means of bolts 13.

By using two separate spaced barriers intermediate adjacent sets of brushes, any are which tends to establish itself is choked at two points spaced from each other. Such arrangement provides a device of double eti'ectiveness of a single barrier, such as has been used heretofore. As one of the barriers is disposed in proximity to each of the brush se a arcs are prevented from rising on the hrushholders, thus providing an additional advantage of the double barrier arrangement.

From the foregoing description, it will be apparent that I have provided flash barriers which will permit of ready access to the ln'ushholders for adjustment thereof; which are so disposed as to smother any are tending to establish itself over the surface of the commutator cylinder and which present no delicate pointed edges to be injured after being placed in position.

\Vhile I have shown my invention in its preferred form, it will be obvious to those skilled in the art that it is susceptible of various minor changes and modifications without departing from the spirit and scope thereof, and I desire therefore that only such lin'iitations shall be placed there-upon are imposed by the prior art or are specifically set forth in the appended claims.

I claim as my invention:

1. In combination, a commutator cylinder, a set of brushes adapted to co-operate therewith, and an arc barrier disposed on each side of said set of brushes, both of said barriers being inclined to such degree that the ends of said barriers adjacent to the comn'iutator cylinder are in proximity to the set of brushes and the opposite ends there of are relatively far apart.

2. In combination, a commutator cylinder, a set of brushes adapted to co-operate therewith, and an arc barrier disposed on each side of said set of brushes, both of said barriers being inclined with respect to a radius of the commutator cylinder passing through the brush set.

3. In combination, a commutator cylinder, a plurality of sets of brushes adapted to co-operate therewith, barriers of insulating material located between adjacent sets of brushes, one of said barriers comprising a relatively short portion disposed substantiall y radially with respect to said commutator cylinder and in proximity thereto and a relatively long main body portion integral with said relatively short portion and disposed at an angle thereto.

4. In con'ibination, a commutator cylinder, a brushholder adapted to co-operate therewith, a barrier disposed in proximity to said cylinder and mounted on said brushholder adjacent a longitudinal face thereof.

5. In combination, a commutator cylinder, a brushholder adapted to co-operate therewith, a barrier of insulating material disposed on each side of said brushholder, both of said barriers being mounted on, and supported from, said brushholder adjacent a longitudinal face thereof.

6. The combination of a brushholder, a brush therefor, an arc barrier disposed on and supported by each side of said brushholder, and means mounted between said are barriers for normally applying pressure to the brush.

7. In, combination, a commutator cylinder, a plurality of brushes adapted to cooperate therewith, holders for said brushes, and a pair of arc barriers carried by each of said holders and disposed on opposite sides of said brushes, respectively, at least one of the barriers of each pair being inclined to increase the distance between the barriers at the ends remote from the commutator cylinder.

In testimony whereof, I have hereunto subscribed my name this 15th day of February, 1922.

ERROL B. SHAND. 

